A large PSNI operation involved several Land Rovers, while a helicopter hovered overhead.

They find a spot for the fight, and one orders the audience to spread out to create a ring.

Then a voice calls out: "Right, go ahead there - go ahead."

As dozens of youths switch on their camerphones, a girl in a purple hoodie and another in a grey tracksuit lunge forward.

They grab each other's hair and flail punches wildly at each other before it quickly comes to an end.

Later, teenagers swarmed around cars to get away from the scene as bewildered Sunday shoppers tried to make their way down Castle Street.

In a statement on Monday police said two 14-year-old females were arrested for disorderly behaviour and will be reported to the Youth Diversion Officer.

A 37-year-old male was also arrested for possession of an offensive weapon and has subsequently been reported to the Public Prosecution Service.

Local Policing Chief Inspector Robert Murdie said: "We know that these fights are being organised through social media and we would urge young people not to get involved in this this type of behaviour.

“We cannot have groups of youths fighting in the streets. Someone will get seriously hurt so we need the support of the community to put a stop to this now.

“Pre-arranged fights may start off between one or two people but could quickly escalate and the potential for serious injury cannot be underestimated. Younger children in particular could find themselves being drawn into a situation that is potentially very dangerous.

“We will continue to monitor reports of pre-arranged fights and respond appropriately, including focusing patrols in certain areas over particular times."

Mr Murdie urged parents to make sure they know where their children are.

He said: “I would urge parents to make sure they know where their children are and what they are doing, and to talk to them about the danger of getting caught up in the moment and the possible outcomes they could face if they are found committing any offence.

“I would also like to remind young people there are consequences when you get involved in this type of behaviour. What might seem like fooling about can often result in a criminal record which can affect travel, education and employment opportunities in the future. It is really important that young people understand this.

“If you are aware of antisocial behaviour or any pre-arranged fights in your area please contact your neighbourhood policing team on the non-emergency number 101 and let us know so that we can respond and find ways to address problems.”

Social media was ablaze with comments after the rowdy scenes, which were also captured on camera and posted on the internet.

One Facebook user said: "Seen the video and it is disgusting, getting on like animals in the city centre.

"Hope the girls arrested get dealt with and as for the 200 watching they are just as bad."

Another Facebook user stated: 'We came through town. Knew there was something going on as children were coming into town in droves and police were sending them back - wouldn't let them through.

"Can't believe it was to see two children fighting, because that's what they were - children. Dear God. Parents, where are you? This is not police business it's yours."

Another user said: "I walked past with my two young children. All I said to them was, 'Please do not do anything like that at their age.' Some of them as young as about 11-12. Do parents not keep an eye on their kids?"

Another Facebook comment said: "If police officers did not have to respond to such rubbish they would have more time for more serious matters."

Some people wished to stress that not all young people are bad.

One Facebook comment said: "It's people like this that make this generation look so bad. As hard as it is to believe, there are a lot of good, kind and smart people here. Not only adults but also kids and teenagers."

Background

The role of social media in the lives of young people is in the spotlight after police said they believed the Belfast city centre fight was pre-arranged via the internet.

In March, police said a fight at a north Belfast interface was the latest in a spate of gatherings arranged by young people across the city on Facebook.